General science, engineering & technologyhttp://hdl.handle.net/10204/12
Thu, 21 Mar 2019 09:54:14 GMT2019-03-21T09:54:14ZA data privacy model based on Internet of Things and cyberphysical systems reference architectureshttp://hdl.handle.net/10204/10811
A data privacy model based on Internet of Things and cyberphysical systems reference architectures
Baloyi, Ntsako; Kotzé, P
Data privacy concerns in the Internet of Things (IoT) and cyberphysical systems (CPS) are real, valid and accentuated. In this paper it is argued that data privacy compliance in IoT and CPS should be addressed at both technical and non-technical levels. Methods to ensure data privacy protection based on both system and organisational reference architectures are therefore required. Based on an analysis of existing reference architectures for IoT and CPS, this paper proposes a consolidated architecture relevant for ensuring data privacy for both IoT and CPS. The proposed architecture is then combined with an enterprise architecture reference framework to propose a data privacy model for IoT and CPS with a focus on both organisational and technological features and positioned to guide compliance with the South African Protection of Personal Information Act 4 of 2013 (POPI Act).
Copyright: 2018 ACM. Due to copyright restrictions, the attached PDF file only contains the abstract of the full text item. For access to the full text item, please consult the publisher's website.
Sat, 01 Sep 2018 00:00:00 GMThttp://hdl.handle.net/10204/108112018-09-01T00:00:00ZProbing the electrochemistry of MXene (Ti2CTx)/electrolytic manganese dioxide (EMD) composites as anode materials for lithium-ion batterieshttp://hdl.handle.net/10204/10810
Probing the electrochemistry of MXene (Ti2CTx)/electrolytic manganese dioxide (EMD) composites as anode materials for lithium-ion batteries
Melchior, SA; Palaniyandy, Nithyadharseni; Sigalas, I; Iyuke, SE; Ozoemena, KI
The performance of MXenes (Ti2CTx) combined with electrolytic manganese dioxide (EMD) in three different weight ratios (i.e. MXene:EMD = 20:80; 50:50; 80:20) were examined as anode material for Lithium-ion batteries (LIBs). A study of the structure, composition and morphology of the synthesized materials was conducted. The materials were further investigated for their electrochemical properties in a half-cell configuration using impedance spectroscopy measurements, cyclic voltammetry and galvanostatic charge-discharge cycling. Results showed that the combined MXene/EMD material has a greater cycling stability, capacity and rate capability as compared to the EMD. The best ratio was found to be MXene:EMD = 80:20. The capacity obtained for this material after 200 cycles is 460 mA h g-1 at a current density of 100 mA g-1. The Li-ion accessibility improved with cycling. This study provides a first insight into the viability of using one of the lightest known MXenes and EMD composite for improved LIB anodes. As EMD is a low cost and abundant material, it provides great opportunities for improved capabilities for lightweight applications at an affordable cost.
Copyright: 2018 Elsevier. Due to copyright restrictions, the attached PDF file only contains the abstract of the full text item. For access to the full text item, please consult the publisher's website. The definitive version is available from https://doi.org/10.1016/j.electacta.2018.12.013
Fri, 01 Feb 2019 00:00:00 GMThttp://hdl.handle.net/10204/108102019-02-01T00:00:00ZIdentification and characterisation of typical solid biowaste residues in South Africa: Potential feedstocks for waste-to-energy technologieshttp://hdl.handle.net/10204/10809
Identification and characterisation of typical solid biowaste residues in South Africa: Potential feedstocks for waste-to-energy technologies
Tawona, N; Sithole, Bishop B; Parkin, J
The suitability of different technology solutions for the beneficiation of biowaste is dependent on the physical and chemical properties of the specific waste stream. This research was undertaken as part of the EU FP7 funded Biowaste4SP project, which entailed beneficiation of biowaste via generation of biogas and production of compost – thus benefitting communities in developing countries in terms of avoidance of landfilling and generation of high value materials from biowaste. A study was conducted to identify and characterise the various solid biowaste streams available in South Africa with the ultimate aim of converting the waste into valuable products via waste-to-energy technologies to avoid their disposal by landfilling. Samples were collected from within the KwaZulu-Natal, Gauteng and Limpopo provinces. Representative samples for the identified streams were collected for analysis. The analytical tests performed for the characterisation of the solid biowaste residues included proximate and ultimate analysis, moisture content determination, ash content analysis, and strong acid hydrolysis for determination of total carbohydrates and acid insoluble material. Twelve biowaste types were identified. Sawdust had the highest volatile solids (VS) content (93%) whereas soybean waste and water hyacinth had the lowest VS content (63%). Elemental analysis results revealed that sugar cane bagasse, vegetable waste and banana (whole fruit) were highly carbonaceous (C > 40%) and furthermore, that sugar cane bagasse had the highest carbon : nitrogen (C : N) ratio (246.6:1). The results indicated that banana biowaste is suitable for conversion into biogas.
Due to copyright restrictions, the attached PDF file only contains the abstract of the full text item. For access to the full text item, please consult the publisher's website.
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10204/108092018-01-01T00:00:00ZCapacity and charge-transport enhancement of LFP/RGO by doping with a-MnO2 in a microwave-assisted synthesishttp://hdl.handle.net/10204/10808
Capacity and charge-transport enhancement of LFP/RGO by doping with a-MnO2 in a microwave-assisted synthesis
Rossouw, Claire A; Raju, Kumar; Zheng, Haitao; Ozoemena, KI
Manganese-doped lithium iron phosphate (LFMP), coated with reduced graphene oxide (RGO), has been prepared by a microwave-assisted solvothermal technique. The un-doped lithium iron phosphate material with RGO (i.e., LFP/RGO) gave a rod-like morphology (> 200 nm in length), while the LFMP/RGO gave a sponge-like spherical morphology (≥ 100 nm diameter). This dramatic change in morphology upon doping with Mn from α-MnO2 resulted in improved coin cell performance in terms of capacity, coulombic efficiency and charge-transfer properties. The increased performance can be attributed to improved particle size and higher surface area owing to the partial substitution of Mn ions for Fe ions. LiFe0.8Mn0.2PO4 synthesised using microwaves provides a quicker method of synthesis while providing a cathode material with a promising capacity.
Copyright: 2017 Springer. Due to copyright restrictions, the attached PDF file only contains the abstract of the full text item. For access to the full text item, please consult the publisher's website. A free fulltext readable version of the item can be accessed via https://rdcu.be/brWNi
Fri, 01 Dec 2017 00:00:00 GMThttp://hdl.handle.net/10204/108082017-12-01T00:00:00Z